It was just blocks from where then nine-year-old Cooper Stock was hit by a speeding taxi while crossing the street five years ago.

Avery Dermer was his childhood friend.

“I’m here today because Cooper is not. He never got the chance to become a teenager and develop into his own person.”

Avery and others who have lost loved ones in traffic accidents joined Mayor de Blasio to announce the dramatic expansion of the program.

All 750 school zones will get speed cameras. The city is doubling of enforcement hours, which will now be from 6 a.m. to 10 p.m. on weekdays year-round. The fine is $50.

Amy Cohen’s son, Sammy Cohen Ekstein, was 12 when he was killed in a 2013 accident as he chased a soccer ball across Prospect Park West.

“I challenge everyone who dares complain that they get a $50 slap on the wrist… a little modest fine for engaging in a behavior that could kill someone. I dare them to come talk to me… and hear the heartache they could have caused by their behavior,” Cohen argued.

The speed cameras will be calibrated to give you a ticket if you go 36 miles an hour or higher. That’s 11 miles over the speed limit.

City officials said you normally get a ticket from going 10 miles over the limit, but they added an extra mile to avoid motorists’ challenges.

Mayor de Blasio defended the expansion, claiming it’s not about the money.

“We don’t want the revenue, we want people to stop speeding.”

The mayor also wants the state legislature, which had to approve the increase in cameras, to go even further.

De Blasio is calling for legislation to increase the fines for multiple violations and to suspend the licenses of repeat offenders.

“Over 80 percent of people once they get that first speeding ticket they don’t get another,” transportation commissioner Polly Trotteneberg said.

Last year the city collected $45 million from the speed camera program. The city plans to start installing the cameras at the new school zone locations at the rate of about 40 a month.